For persons who cannot control excretion of feces or urine by their will or persons with diseases of organs of the digestive system or the urinary system, a surgical operation is performed to draw the intestinal tract or the ureter to the body surface to form an opening referred to as a stoma on the body surface. In this case, persons with a stoma (hereinafter sometimes referred to as a “stoma holder”) need to have an ostomy appliance capable of temporarily storing excrement from the stoma attached to the surrounding of the stoma. The ostomy appliance contains a pouch for storing excrement and a pressure-sensitive adhesive sheet referred to as a face plate and is used by adhering and fixing the face plate to the surrounding of the stoma.
For the face plate of the ostomy appliance, a so-called hydrocolloid pressure-sensitive adhesive agent for skin containing hydrophilic polymer compounds is generally used so as to absorb the moisture from the skin or excrement even when adhered to the skin over a long period of time (e.g., Patent Documents 1 to 9).
It is also important for the face plate of the ostomy appliance to maintain the balance of aggregation properties, shape retention properties, and skin-follow up properties in addition to satisfying the water absorption properties.
Some former face plates can absorb much moisture, but the aggregation properties are not sufficient. Thus, a pressure-sensitive adhesive agent for skin has leaked out from the outer peripheral edge of the face plate after water absorption or an adhesive residue has been left after separation in some cases. Former face plates having increased aggregation properties or shape retention properties have poor water absorption properties or skin-follow up properties in some cases, and thus the face plate has separated when adhered over a long period of time or unpleasantness has arisen during adhesion in some cases.
Moreover, since the stoma holders use the ostomy appliance over a long term, the physiological function (skin barrier function) of the skin decreases to easily cause dermatitis or the like due to repeated adhering and separating of the face plate.
The pressure-sensitive adhesive agent for skin or pressure-sensitive adhesive sheet for skin for use in wound bandages or the like has also been desired to promptly absorb the blood, exudate, or the like, have favorable adaptability to the diseased part when adhered over a long period of time, and leave no adhesive residue after separation.    [Patent Document 1] Japanese Examined Patent Application Publication No. 6-14957    [Patent Document 2] Japanese Patent No. 2947728    [Patent Document 3] Japanese Examined Patent Application Publication No. 62-47545    [Patent Document 4] Japanese Patent No. 3471122    [Patent Document 5] Japanese Unexamined Patent Application Publication No. 6-200    [Patent Document 6] Japanese Unexamined Patent Application Publication No. 5-123389    [Patent Document 7] Japanese Examined Patent Application Publication No. 6-78507    [Patent Document 8] Japanese Unexamined Patent Application Publication No. 2004-305725    [Patent Document 9] Japanese Unexamined Patent Application Publication No. 2006-263042